Introduction: Thymus vulgaris is used in traditional medicine to treat ga- strointestinal diseases because of its antifungal, antibacterial, and antispas- modic activity. Objective: To verify whether Thymus vulgaris also has anti- protozoal activity against Trichomonas vaginalis , Giardia lamblia and Enta- moeba histolytica trophozoites. Materials and methods: Conventional cul- tures of parasites were measured on the third day during the logarithmic growth phase. The antiprotozoal activity of the methanol extract and its frac- tions were evaluated comparing growth in cultures with and without extracts. Next, the extract was fractionated by polarity-based partitioning. Then, the purity of each fraction was determined by thin layer chromatography (TLC). The percentage of growth inhibition was calculated with respect to untreated controls. The 50% inhibitory concentration (IC 50 ) of each extract was calcu-
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Benzimidazole derivatives are of wide interest because of their diverse biological activityand clinical applications . This ring system is present in numerous antiparasitic, fungicidal, anithelemintic and anti-inflammatory drugs [2– 5]. Also, some benzimidazole nucleosides, particularly 5,6-dichlorobenzimidazole-1-_-D-ribofuranoside (DRB) and its 2-substituted derivatives show activity against human cytomegalovirus . It is also known that 5,6- dinitrobenzimidazole can substitute 5,6-dimethylbenzimidazole in the vitamin B12 molecule in Corynebacterium diphteriae  and 2-trifluorobenzimidazoles are potent decouplers of oxidative phosphorylation in mitochondria. They are also inhibitors of photosynthesis, and some exhibit appreciable herbicidal activity . Most recently, antiprotozoal activity of substituted 2-trifluorobenzimidazoles has been reported , consistent with several earlier studies on the anti-giardial activity of various benzimidazole derivatives [10, 11]. However, the general antimicrobial activity of benzimidazole derivatives has not been extensively investigated. The earliest report of their antibacterial activity appeared in 1964 , and more recently we have found two groups of substituted benzimidazoles, namely the 5,6-dinitro and 2-trifluoromethyl derivatives, to be promising candidates for antimicrobial drugs . In this paper we present new data on the antimicrobial and antiprotozoal activities of 5,6- dinitro and 2-dialkylaminosubstituted benzimidazoles.
Neglected diseases like leishmaniasis and trypanosomiasis still remain a serious Public Health problem throughout the world with severe socio-economic impacts. There is an urge for new therapeutic alternatives and Annona essential oils have showed to be active against some of their protozoan agents, therefore encouraging this study. The volatile oil from the leaves of A. crassiflora (Mart.) (Annonaceae) was isolated (0.06% w/ w) in a Clevenger-type apparatus and analysed by GC-MS and GC-FID. Among the 41 identified compounds (83.2 %), sesquiterpenes were predominant (81.7 %), followed by monoterpenes (0.8 %) and other metabolites. The major constituents were α-amorphene (43.6 %), E-caryophyllene (17.7 %) and germacrene (5.3 %). The antiprotozoal activity was evaluated against four Leishmania species and T. cruzi, determining the parasites viability by MTT assay. The oil was mostly active in the promastigotes of L. (L.) infantum chagasi (IC 50 : 25.97 µg/ mL), while the activity against T.cruzi trypomastigotes (IC 50 : 5.31 µg/ ml) was nine folds higher
Five methanol extracts of five plant species belonging to five families collected from Albaha region (Table 1) were investigated for their antiprotozoal and cytotoxic activity against P. falciparum, L. infantum, T. cruzi, T. brucei and MRC-5 cells, respectively (Table 2). The listed IC50 values are the means of three determinations. Particularly for natural products, evaluation of selectivity is essential and represented as the selectivity index (SI): ratio (CC50 MRC-5 cells/IC50 protozoa). An acceptable criterion for activity was an IC50<10 μg ml -1 and a selectivity index (SI) of >4. Indeed, in evaluating the selectivity against protozoan versus mammalian cells, it is noted that the antiprotozoal activities of most active extracts may be due to their cytotoxicity to mammalian cells, as is demonstrated by the moderate, low or very low SI-values between <1 and 3.5.
Rubus liebmanii is used in Mexican traditional medicine to treat cough, nervous conditions, insomnia and dysentery. There are not biological and chemical reports from this specie; however, in other species of the genus, many compounds with important biological activity have been isolated. The ethanolic extract of aerial parts showed antiprotozoal activity against Entamoeba histolytica, Trychomonas vaginalis and Giardia lambia, with values inhibition 10, 12, and 4% at 100µg/mL, respectively. Against G. intestinalis presented an IC 50 =11.75µg/mL. Low toxicological effect
has a considerable impact on antibacterial and antifungal activity. Also chloro and nitro group shows considerable effect on antiprotozoal activity. All the synthesized compounds exhibited better antiprotozoal activity towards Paramecium caudatum, Vorticella campanula, some of the synthesized compounds showed good antiprotozoal activity. From Tables 4, it can be inferred that as the number of carbon atom increases in side chain at 2- position of oxadiazole heterocyclic ring causes an increase in the intensity of the activity against Paramecium caudatum, Vorticella campanula , Opalina ranarum and also the para substitution on benzene nucleus at oxadiazole moiety supports the chemotherapeutic activity. While 5,6-dinitro and 4,6- dichlorobenzimidazoles with oxadiazole heterocyclic ring have potent antiprotozoal activity.
Giardia lamblia is an important cause of acute and chronic gastrointestinal disease throughout the world and has been identified as the etiologic agent in numerous waterborne outbreaks of diarrheal disease. Although G. lamblia is among the most prevalent enteric protozoal infections in humans, it is relatively recently that improvements in the in vitro cultivation of this organism have allowed reliable, reproducible tests to assess the in vitro activity of therapeutic agents against G. lamblia . Despite the previous comprehensive screening of Sudanese medicinal plants for their antiprotozoal activity [28-29-30-31-32].
With respect to the level of activity showed by respect- tive reference products against these selected protozoa, it was however seen that the samples Sd-1, Sd-2 and Sd-3 showed higher cytotoxic effect (19.4, 6.8 and 24.4-times more cytotoxic) than tamoxifen, against MRC-5 cell lines growth, Sd-1, Sd-1.2.2 and Sd-3 exhibited higher activity (1.7, 8 and 2-times more cytotoxic) than benzni- dazol against T. cruzi growth, while the activity of Sd-2 was comparable to that of this reference product against this parasite. Sd-1 and Sd-1.2.2 displayed higher activity (2 and 19-times more cytotoxic) than miltesfosine against L. infantum growth. The activity of Sd-1, Sd-1.2.2, Sd-2 and Sd-3 was comparable to that of chloroquine against chloroquine and pyrimethamine-resistant K1strain of P. falciparum. On the other hand, it is well known that compounds responsible for the antiplasmodial activity of B. sumatrana seeds growing in Asian regions are quassi- noids. These compounds were also recognized be re- sponsible for the antiprotozoal activity against Trypano- soma evansi infecting animals , but compounds ac- tive against other Trypanosoma and Leishmania specie from this plant part are still unknown. This finding dem- onstrates that these samples need extensive phytochemi- cal investigations leading to the isolation and structural elucidation of active principles which would be consid- ered as lead compounds.
Stevia a „Latin American herb‟ is the world‟s only natural sweetener with zero calories, zero carbohydrates and a zero glycemic index. In the present investigation, the in vitro regeneration of Stevia rebaudiana was performed through callogenesis and organogenesis from different explants (Leaves, Inter node, Shoot discs). Leaves explants showed best callus induction response when cultured on MS + (2.0 µM BAP + 1.0 µM NAA). However, the best callus initiation from leaf explants was obtained on MS medium supplemented with 1.0 µM NAA + 1.0 µM Kn. Optimization results of medium type and carbon source confirm 1X MS medium and glucose (3%) respectively best for callus initiation. Shoot initiation was achieved on 1X MS medium supplemented with 5.0 µM BAP + 1.0 µM NAA. In vitro raised shoots of Stevia showed best rooting on 1X MS + (1.0 µM IAA). The methanolic extracts of regenerated plants and callus culture of Stevia showed best antibacterial and antifungal activity against a number of microorganisms. Antiprotozoal activity of methanolic extract was also tested and found satisfactory. In vitro regeneration protocol of Stevia through callus culture is advantageous for enhanced multiplication of superior Stevia cultivars. Furthermore, callus from leaf explants can be a good source for production of antimicrobial and antiprotozoal compound of Stevia through bioreactor.
responsible for the activity against two anaerobic para- sites that cause diarrhea: G. lamblia, and E. histolytica. The in vitro and in vivo giardicidal activity of epicatechin isolated from plants such as Rubus coriifolius and Heliantemum glomeratus has been reported [29,30]. In this regard, epicatechin was detected in P. americana EtOH seed extract by TLC analysis; hence, this compound may be responsible for the giardicidal activity observed in this study. Further studies are required to define the active compound(s) responsible for the antiprotozoal activity of the CHCl 3 extract.
(Supplementary Figure 2a), we hypothesized that: (i) interactions of 6’-F sisomicin with the bacterial ribosome A-site should be disrupted due its inability to form a stable pseudo base-pair interaction with the A1408 nucleobase. Interestingly, the X-ray co-crystal structure of 6’-F sisomicin in complex with the palindromic RNA duplex comprising two identical bacterial A-sites displays a pose for the 6’-F ring I that was out of register with the highly specific hydrogen-bond and stacking interactions made by numerous aminoglycoside antibiotics (ii) 6’- F-sisomicin should exhibit antiprotozoal activity due to its H-bond acceptor ability with G1408.. (iii) the parent sisomicin should experience ineffective binding to the protozoal cytoplasmic ribosome A-site, since the 6-NH 3 + in ring I would act as a
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forms LC(50) of T. cruzi, causal organism of chagas disease, shows a significant inhibition of the parasite mainly due to the presence of chemical substances monoterpenes and sesquiterpenes in all the products.  A study in Cameroon contends that Nefang a polyherbal anti-malarial folklore medicine with O. gratissimum leaves as an important constituent, exhibit an excellent action against multi-drug resistant Plasmodium falciparum along with in vivo suppression of P. berghei and P. chabaudi malaria parasites.  Accordingly, when the evaluation of ten plant species against bloodstream strains of Trypanosoma brucei rhodesiense was carried out, it was noted that the ethyl acetate leaf extract of O. gratissimum expressed highest activity IC(50) value of 2.08 0.01 μg/ml and a high selective index of 29 against the protozoan.  Moreover, a recent study on use of lemon basil oil against L. amazonensis also provided evidence of the leishmanicidal activity of the plant. 
65. Smith, P.W., Wymana, P.A., Lovell, P., Goodacre, C., Serafinowska, H.T., Vong, A., Harrington, F., Flynn, S., Bradley, D.M., Porter, R., Coggon, S., Murkitt, G., Searle, K., Thomas, D.R., Watson, J.M., Martin, W., Wu, Z., Dawson, L.A., 2009. New quinoline NK3 receptor antagonists with CNS activity. Bioorg. Med. Chem.Lett. 19, 837–840.
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Antioxidant activity: The antioxidant activity of OS has been reported by many workers. [8-11] The antioxidant properties of flavonoids and their relation to membrane protection have been observed.  Antioxidant activity of the flavonoids (orientin and vicenin) in vivo was expressed in a significant reduction in the radiation induced lipid peroxidation in mouse liver.  OS extract has significant ability to scavenge highly reactive free radicals.  The phenolic compounds, viz., cirsilineol, cirsimaritin, isothymusin, apigenin and rosmarinic acid, and appreciable quantities of eugenol (a major component of the volatile oil) from OS extract of fresh leaves and stems possessed good antioxidant activity. 
Tinidazole, a synthetic nitroimidazole, a structural analogue of metronidazole, is an antiprotozoal agent that has been widely used for more than two decades with established efficacy and acceptable tolerability for the treatment of trichomoniasis, giardiasis, amebiasis, and amebic liver abscess. Although oral delivery has become a widely accepted route of administration of therapeutic drugs, the gastrointestinal tract presents several formidable barriers to drug delivery. Colonic drug delivery has gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon but also for its potential for the delivery of proteins and therapeutic peptides.
including traces of compounds down to parts per trillions in some particular cases. The significance of gas chromatography in quality control and process control in the chemical and drug industry, in environmental pollution investigations and in clinical analysis is critical.  In the recent years, Gas Chromatography Mass Spectrometry (GC-MS) is strongly recognized as a tool to identify the chemical composition of medicinal plants. [27-29] In the present study also we used the GC-MS analysis to know the chemical constituents of A. lebbeck leaves. The result of GC-MS analysis revealed the chemcial composition of A. lebbeck leaves and the results were tabulted in table 1-3. Any biologically active compound has a wide spectrum of effects. Some of them are useful in the treatment for diseases, but the others cause various toxic effects. The global research scenario recommends the use of virtual screening techniques for the discovery of bioactive phytoconstituents. Computer-aided methods could be extremely useful in pharmacological evaluation of NPs.  To analyze the biological and toxic effects, there are many software programs are available on the internet. PASS is one of the main programs to analyze the total complex activity of the compound on a biological entity and biological activity spectrum of the substance.  The current version of PASS predicts around 3750 pharmacological effects, biochemical mechanisms of action, speciﬁc toxicities and metabolic terms on the basis of structural formulae of drug-like substances with average accuracy of 95%. This can be further validated in in-vitro as well as in-vivo assays. [32-33] A number of researchers applied the PASS prediction for their biological activity analysis viz., Anti-tumor, anti-malarial, Anit-HIV and other. [34-42] In the present study also we applied the PASS prediction for the predicted compounds using GC-MS analysis. Pa (Probability to be active) and Pi (probability to be inactive) were estimates of probability for the compound to be active and inactive respecitvely for each type of activity from the biological activity spectrum. Their values vary from 0.0000 to 1.0000.
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CONCLUSION: Investigation of the chloromethylenic extract of the roots of Uvaria afzelii has led to the isolation of two β-triketone derivatives, bingervone (1) and emorydone (3). β- Triketone derivatives were found to have limited occurrence in plant kingdom. The third compound, demethoxymatteucinol (2), was a C-methylated flavanone previously obtained from U. afzelii. Their structures were determined thanks by NMR, UV, IR and HRESIMS spectroscopic data. The unusual β-triketone derivative, bingervone, showed antiprotozoal activities on Leishmania donovani and L. major similar to those of sitamaquine. Thus, it is worth to be studied in other in vitro and in vivo models for leishmaniasis experiments.
Melarsoprol can induce a life-threatening encephalopathy in large numbers of patients (Seixas 2005) and trials assessing melarsoprol have been aimed at minimizing doses of the drug and length of treatment while maintaining anti-trypanosome activity. Fixed 10-day regimens were found to be as effective as those of 26 days and resulted in similar levels of adverse events (Burri 2000 and Pepin 2006). They offer however significant practical advantages (fewer painful injections, less drug used and shorter treatment duration). Slightly different graded 26-day melarsoprol regimens were used in Burri 2000 and Pepin 2006, and an incremental 10-day regimen was tested in Bisser 2007. Although Burri 2000 did not report differences in outcomes or adverse events between the graded schedule and the 10-day schedule, the other two trials showed that graded or incremental melarsoprol resulted in higher death rates, higher number of seizures (Pepin 2006) and more relapses (Bisser 2007), suggesting that incremental melarsoprol schedules should be abandoned (Pepin 2006).
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The carotene and lutein contents of the leaves were higher than those of cabbage, but lower than those of amaranth . Carotenoids have been widely accepted as safe chemicals for food supplementation and neutra- ceutical purposes due to their intense coloring abilities, their role as precursors of vitamin A, and their antioxi- dant activity in animals  . They have been shown to be beneficial in preventing major health problems in developing and developed countries, including cancers, cardiovascular and coronary heart diseases, photosensi- tivity disorders, age-related macular degeneration and cataract . Carotenes and lutein protect against uterine, prostate, breast, colorectal and lung cancers . Carotenes, in addition, have pro-vitamin A and antioxidant  activities.
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Results: In initial period (no intervention) doctors were prescribing antibiotics for 51.4% of case of non-bloody diarrhoea. In the Second intervention period there were few cases, but it is remarkable how few were prescribed antibiotic (19%) while the survey of prescribing habits was underway. In the Third intervention period when an education event took place, it was the peak of the diarrhoea season. Prescribing increased somewhat to 28.2%. In the Forth intervention a letter was sent out to the doctors describing the results so far, and pointing out the lower prescribing by “senior doctors”. The overall changes in prescribing behaviour after the educational interventions were statistically significant. The reduction in prescribing noted when comparing intervention 1 and intervention 4, is highly significant (antibiotic p < 0.001, anti-protozoal p<0.001). In the Fifth intervention period when appropriate prescribing was no longer actively promoted, the rate of prescribing increased again to 40.8% of cases. A similar pattern is noted for antiprotozoal prescribing. The increase in prescribing noted in the Fifth period was still less than in the First period (antibiotic p=0.041, anti- protozoal p=0.055). The increase in prescribing from periods Forth to Fifth was significant. (Antibiotics p<0.001, anti-protozoal p = 0.012).